Android 开发中，经常需要对图片进行二次处理，比如添加圆角效果 或 显示圆形图片；
方法一
通过第三方框架 Glide 设置圆角效果；
写法1：
RequestOptions options = new RequestOptions().error(R.drawable.img_load_failure).bitmapTransform(new RoundedCorners(30));//图片圆角为30
Glide.with(this).load(URL) //图片地址
.apply(options)
.into(ImagView);
写法2：
RequestOptions requestOptions = new RequestOptions();
requestOptions.placeholder(R.drawable.ic_launcher_background);
requestOptions.circleCropTransform();
requestOptions.transforms( new RoundedCorners(30));
Glide.with(this).load(URL) //图片地址
.apply(options)
.into(ImagView);
写法3：
RequestOptions options = new RequestOptions().centerCrop() .transform(new RoundTransform(this,30));
Glide.with(this).load(URL) //图片地址
.apply(options)
.into(ImagView);
public class RoundTransform extends BitmapTransformation {
private static float radius = 0f;
public RoundTransform(Context context) {
this(context, 4);
}
public RoundTransform(Context context, int dp) {
super(context);
this.radius = Resources.getSystem().getDisplayMetrics().density * dp;
}
@Override
protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
Bitmap bitmap = TransformationUtils.centerCrop(pool, toTransform, outWidth, outHeight);
return roundCrop(pool, bitmap);
}
private static Bitmap roundCrop(BitmapPool pool, Bitmap source) {
if (source == null) return null;
Bitmap result = pool.get(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);
if (result == null) {
result = Bitmap.createBitmap(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);
}
Canvas canvas = new Canvas(result);
Paint paint = new Paint();
paint.setShader(new BitmapShader(source, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));
paint.setAntiAlias(true);
RectF rectF = new RectF(0f, 0f, source.getWidth(), source.getHeight());
canvas.drawRoundRect(rectF, radius, radius, paint);
return result;
}
public String getId() {
return getClass().getName() + Math.round(radius);
}
@Override
public void updateDiskCacheKey(MessageDigest messageDigest) {
}
}
方法二
自定义ImageView 设置圆角效果；
ImageView iv = findViewById(R.id.iv);
Bitmap bitmap =BitmapFactory.decodeResource(getResources(), R.drawable.fengjing);
Bitmap outBitmap =getRoundBitmapByShader(bitmap, 500,300,20, 3);
iv.setImageBitmap(outBitmap);
public class RoundRectImageView extends ImageView{
private Paint paint;
public RoundRectImageView(Context context) {
this(context,null);
}
public RoundRectImageView(Context context, AttributeSet attrs) {
this(context, attrs,0);
}
public RoundRectImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
paint = new Paint();
}
/**
* 绘制圆角矩形图片
*/
@Override
protected void onDraw(Canvas canvas) {
Drawable drawable = getDrawable();
if (null != drawable) {
Bitmap bitmap = getBitmapFromDrawable(drawable);
// Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
Bitmap b = getRoundBitmapByShader(bitmap,getWidth(),getHeight(), 50,0);
final Rect rectSrc = new Rect(0, 0, b.getWidth(), b.getHeight());
final Rect rectDest = new Rect(0,0,getWidth(),getHeight());
paint.reset();
canvas.drawBitmap(b, rectSrc, rectDest, paint);
} else {
super.onDraw(canvas);
}
}
/**
* 把资源图片转换成Bitmap
* @param drawable
* 资源图片
* @return 位图
*/
public static Bitmap getBitmapFromDrawable(Drawable drawable) {
int width = drawable.getIntrinsicWidth();
int height = drawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(width, height, drawable
.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
: Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
//drawable.setBounds(-4, -4, width + 4, height + 4);
drawable.draw(canvas);
return bitmap;
}
public static Bitmap getRoundBitmapByShader(Bitmap bitmap, int outWidth, int outHeight, int radius, int boarder) {
if (bitmap == null) {
return null;
}
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float widthScale = outWidth * 1f / width;
float heightScale = outHeight * 1f / height;
Matrix matrix = new Matrix();
matrix.setScale(widthScale, heightScale);
//创建输出的bitmap
Bitmap desBitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.ARGB_8888);
//创建canvas并传入desBitmap，这样绘制的内容都会在desBitmap上
Canvas canvas = new Canvas(desBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
//创建着色器
BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
//给着色器配置matrix
bitmapShader.setLocalMatrix(matrix);
paint.setShader(bitmapShader);
//创建矩形区域并且预留出border
RectF rect = new RectF(boarder, boarder, outWidth - boarder, outHeight - boarder);
//把传入的bitmap绘制到圆角矩形区域内
canvas.drawRoundRect(rect, radius, radius, paint);
if (boarder > 0) {
//绘制boarder
Paint boarderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
boarderPaint.setColor(Color.GREEN);
boarderPaint.setStyle(Paint.Style.STROKE);
boarderPaint.setStrokeWidth(boarder);
canvas.drawRoundRect(rect, radius, radius, boarderPaint);
}
return desBitmap;
}
}
方法三
对图片进行处理，还可以加边框；
/**
* 通过BitmapShader实现圆形边框
* @param bitmap
* @param outWidth 输出的图片宽度
* @param outHeight 输出的图片高度
* @param radius 圆角大小
* @param boarder 边框宽度
*/
public static Bitmap getRoundBitmapByShader(Bitmap bitmap, int outWidth, int outHeight, int radius, int boarder) {
if (bitmap == null) {
return null;
}
int height = bitmap.getHeight();
int width = bitmap.getWidth();
float widthScale = outWidth * 1f / width;
float heightScale = outHeight * 1f / height;
Matrix matrix = new Matrix();
matrix.setScale(widthScale, heightScale);
//创建输出的bitmap
Bitmap desBitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.ARGB_8888);
//创建canvas并传入desBitmap，这样绘制的内容都会在desBitmap上
Canvas canvas = new Canvas(desBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
//创建着色器
BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
//给着色器配置matrix
bitmapShader.setLocalMatrix(matrix);
paint.setShader(bitmapShader);
//创建矩形区域并且预留出border
RectF rect = new RectF(boarder, boarder, outWidth - boarder, outHeight - boarder);
//把传入的bitmap绘制到圆角矩形区域内
canvas.drawRoundRect(rect, radius, radius, paint);
if (boarder > 0) {
//绘制boarder
Paint boarderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
boarderPaint.setColor(Color.GREEN);
boarderPaint.setStyle(Paint.Style.STROKE);
boarderPaint.setStrokeWidth(boarder);
canvas.drawRoundRect(rect, radius, radius, boarderPaint);
}
return desBitmap;
}
实现圆形和边框：
/**
* 通过BitmapShader实现圆形边框
* @param bitmap
* @param outWidth 输出的图片宽度
* @param outHeight 输出的图片高度
* @param boarder 边框大小
*/
public static Bitmap getCircleBitmapByShader(Bitmap bitmap, int outWidth, int outHeight, int boarder) {
int radius;
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float widthScale = outWidth * 1f / width;
float heightScale = outHeight * 1f / height;
Bitmap desBitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.ARGB_8888);
if (outHeight > outWidth) {
radius = outWidth / 2;
} else {
radius = outHeight / 2;
}
//创建canvas
Canvas canvas = new Canvas(desBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
Matrix matrix = new Matrix();
matrix.setScale(widthScale, heightScale);
bitmapShader.setLocalMatrix(matrix);
paint.setShader(bitmapShader);
canvas.drawCircle(outWidth / 2, outHeight / 2, radius - boarder, paint);
if (boarder > 0) {
//绘制boarder
Paint boarderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
boarderPaint.setColor(Color.GREEN);
boarderPaint.setStyle(Paint.Style.STROKE);
boarderPaint.setStrokeWidth(boarder);
canvas.drawCircle(outWidth / 2, outHeight / 2, radius - boarder, boarderPaint);
}
return desBitmap;
}
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